Patent Document 1 discloses a glass panel unit. The glass panel unit described in Patent Document 1 includes a first pane of glass and a second pane of glass that faces the first pane of glass with the two panes of glass spaced a predetermined interval apart. It is also provided with a seal that is disposed between the first pane of glass and the second pane of glass and is joined to them in an airtight manner, and an interior space encompassed with the first pane of glass, the second pane of glass and the seal. It is further provided with a partition wall that is disposed in the interior space and divides the interior space into a first space as a vacuum space and a second space, and an air release vent that is formed in the first pane of glass or the second pane of glass and communicates with the second space.